This invention relates to a liquid crystal device and a method for same.
Liquid crystal devices have been utilized for microcomputers, wordprocessers, television sets and so forth, as displays thereof. Such a display comprises a pair of substrates with a liquid crystal layer inbetween, and electrode arrangement to apply an electric field to the liquid crystal layer. The electrode arrangement is divided into a plurality of sections by which pixels of the display are formed. With a suitable voltage applied to a particular section of the electrode, a corresponding portion of the liquid crystal layer is subjected to electric field. Namely, in correspondence with the direction of the electric field or whether or not the voltage is applied, the liquid crystal changes its optical characteristics and then images or characters are displayed.
The electrode arrangement is for example comprised of a plurality of first electrode strips arranged in a X direction on the inside of one substrate, and a plurality of second electrode strips arranged in a Y direction on the opposed inside of the other substrate. The strips are formed by lithography with masks (photoresist). Even if the pattern of the electrodes is comparatively simple, the photoetching has to be carried out with special accuracy. Because of this the lithography process requires many steps and eventually the price of the liquid crystal display rises.
To cope with the conventional shortcomings, the applicant has proposed an improved process in which a laser beam having a linear cross section is radiated to a transparent conductive film prepared on a substrate surface other than the periphery, and then the irradiated linear portion of the film is removed by vaporization, so that the remaining conductive film forms electrodes or leads. With this process, dispensed with are a coating step, a prebaking step, an exposure step, a developing step, a postbaking step, an etching step and a step of removing the coated photoresist.
Anyway, it is required in accordance with prior art to mate a pair of substrates and to form electrode pads with high special accuracy, while preparing a connection area for an external flexible connector of a PCB (pring circuit board). For this reason, a spacial margin must be provided adjacent to a sealing resin layer of a panel, as designated by 9 in FIG. 1.
FIG. 1 is a cross section view showing a prior art configuration of a liquid crystal display. The liquid crystal device is provided with a plurality of first electrode strips 2' elongated in the direction perpendicular to the drawing sheet, and a plurality of second electrode 2 strips elongated in the lateral direction, with a liquid crystal layer 5 disposed between a pair of substrates 1 and 1'. Between the electrode arrangement 2 and 2' and a sealing member 6, a margin 9 is designed so that the sealing member 6 shall not extend on the electrode strips 2 and 2'. If the member 6 partially hides the electrode strips, liquid crystal is pushed away from a corresponding portion of the panel and therefore the corresponding displaying portion can not work. The width of the margin is, e.g., 3 to 5 mm. The margin, however, has no function in the finished product. Rather the size of the dispaly is made large by this margin in comparison with the net displaying area of the liquid crystal panel.
Further, in such a flexible electrode circuit, the electrode strips are arranged only with distances of about several hundred micrometers, and thereby the substrates have to be mated with high skill and particular care. This makes the product expensive also due to decreased yield of the product.